Are there any load balancing approaches for employee cases based on complexity score?
It sounds like you're looking at the Partition Problem. https://en.wikipedia.org/wiki/Partition_problem

The task of slicing one set into N sets so that each set is equal or as close to equal as possible.

Obtaining an exact solution is NP-hard (you can't do much better than trying all combinations), however you can get an approximate answer in polynomial time.

Greedy approach:


Create N sets, each initially empty
Sort all items in descending order (by their complexity score)
for each item add it to the set with the lowest sum


If N is large, you may want to put the sets into a min heap/priority queue.